Rather than building plastic filaments layer by layer, a new approach to 3D printing raises complex shapes from a liquid tank up to 100 times faster than conventional 3 – From the printing processes, researchers from the University of Michigan have demonstrated.
3D printing could change the game for relatively small production jobs, producing less than 1
"Using conventional approaches, this is not really achievable unless you have hundreds of machines," said Timothy Scott, associate professor of chemical engineering at the University of New York, who co-directed the development of the new 3-D printing approach with Mark Burns, the TC Chang Professor of Engineering at UM.
Their method solidifies the liquid resin using two lights to control where the resin hardens and where it remains fluid. This allows the team to consolidate the resin into more sophisticated models. They can make a three-dimensional bas-relief in a single shot rather than in a series of 1D lines or two-dimensional sections. Their print demonstrations include a lattice, a toy boat and a block M.
"It's one of the first true 3D printers ever made," said Burns, a professor of chemical engineering and biomedical engineering.
But the true three-dimensional approach is not just acrobatics: it was necessary to overcome the limitations of previous printing presses in the tank. That is to say, the resin tends to solidify on the window the light shines through, stopping the print job just as it starts.
By creating a relatively large region where no solidification occurs, thicker resins, potentially with powder reinforcing additives, can be used to produce more durable objects. The method also improves the structural integrity of 3D filament printing, as these objects have weak points in interfaces between layers.
"It is possible to obtain materials that are much more resistant and much more resistant to wear," Scott said.
A solution before the problem of solidification on the window was a window that lets oxygen pass through. The oxygen penetrates the resin and blocks the solidification near the window, leaving a film of fluid that will allow the newly printed surface to be pulled away.
But since this space is only as large as a piece of transparent tape, the resin must be very liquid to flow quickly enough in the small space between the newly solidified object and the window while the part is pulled toward the surface. ;high. This has limited the printing of the tub to small customized products that will be treated relatively gently, such as dental devices and shoe insoles.
By replacing the oxygen with a second light to stop solidification, the Michigan team can produce a much wider gap in the object and the thickness of the window-millimeter allows the resin to flow thousands of times more quickly.
The key to success is the chemistry of resin. In conventional systems, there is only one reaction. A photoactivator hardens the resin wherever the light shines. In the Michigan system, it is also a photo-inhibitor, which responds to a different wavelength of light.
Instead of just checking solidification in a 2D plane, as current tank printing techniques do, the Michigan team can model the two types of light to harden the resin in virtually any three-dimensional place near the illumination window .
UM filed three patent applications to protect the multiple inventive aspects of the approach and Scott is preparing to launch a startup company.  An article describing this research will be published on Science Advances entitled "Rapid and continuous production of additives by means of volumetric polymerization inhibitory modeling".
Volumetric 3-D printing is based on the need for speed
"Rapid and continuous additive manufacturing by modeling the inhibition of volumetric polymerization" Science Advances (2019). advances.sciencemag.org/content/5/M/eaau8723
University of Michigan
3-D printing 100 times faster with light (2019, January 11)
recovered on January 11, 2019
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